The interaction between laser induced plasma hot core and shock wave was a basic physical phenomenon in the scientific problem of laser induced drag reduction. An experimental platform based on shock tube and laser energy deposition was established, and the high-precision schlieren system was used to capture the flow structure characteristics of laser induced plasma hot core under the normal shock. The experimental results show that the interface of laser induced plasma hot core deforms and bends and finally forms a double vortex ring structure, the width rapidly increases and then decreases and gradually stabilizes at about 7.7 mm, the length decreases first and then linearly increases at a rate of 114.3 m/s after the shock leaves the hot core. The mechanism of laser induced drag reduction was further revealed from the microscopic level, which has good reference value for the related research of plasma induced flow control.